Re: [PATCH 1/3] ACPI / dock: Rework the handling of notifications

From: Yinghai Lu
Date: Fri Jun 28 2013 - 19:34:44 EST


On Fri, Jun 28, 2013 at 3:53 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> The ACPI dock driver uses register_acpi_bus_notifier() which
> installs a notifier triggered globally for all system notifications.
> That first of all is inefficient, because the dock driver is only
> interested in notifications associated with the devices it handles,
> but it has to handle all system notifies for all devices. Moreover,
> it does that even if no docking stations are present in the system
> (CONFIG_ACPI_DOCK set is sufficient for that to happen). Besides,
> that is inconvenient, because it requires the driver to do extra work
> for each notification to find the target dock station object.
>
> For these reasons, rework the dock driver to install a notify
> handler individually for each dock station in the system using
> acpi_install_notify_handler(). This allows the dock station
> object to be passed directly to the notify handler and makes it
> possible to simplify the dock driver quite a bit. It also
> reduces the overhead related to the handling of all system
> notifies when CONFIG_ACPI_DOCK is set.

original change to use register_acpi_bus_notifier, have two assumption
1. two dock_station will have same handle.
2. acpi subsystem: non root acpi device only can have one system
notifier installed.

Maybe you can rework acpi_install_notify_handler to fix 2.

Thanks

Yinghai
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